Explosively actuated fastener driving tool with safety and cartridge extractor means



2,957,176 00L WITH EXTRACTOR MEANS Oct 25, 1960 R. w. HENNING ETALExPLosvELY ACTUATED FASTENER DRIVING T SAFETY AND CARTRIDGE Filed Aug.22, 1955 4 Sheets-Sheet 1 Oct. 25, 1960 R. w. HENNING ETAL 2,957,176EXPLOSIVELY ACTUATED FASTENER DRIVING TOOL WITH SAFETY AND CARTRIDGEEXTRACTOR MEANS Filed Aug. 22, 1955 4 Sheets-Sheet 2 BY .RoGERMARsl-l;

ATTORNEY Oct. 25, 1960 R. w. HENNING ETAL 2,957,176

ExPLosIvELY ACTUATED FASTENER DRIVING Toor. WITH SAFETY AND CARTRIDGEExTRAcToR MEANS Filed Aug. 22, 1955 4 sheets-sheet s mimi INVENTRSIROBERT W. HENNING SNNAJNSPF BY Aruba 5 ATTORNEY o n m mm Oct. 25, 1960R. w. HENNING ETAL 2,957,176

ExPLosIvELY ACTUATED FASTENER DRIVING Toor. WITH SAFETY AND CARTRIDGEEXTRACTOR MEANS Filed Aug. 22. 1955 4 Sheets-Sheet 4 INVENTORS. ROBERTW.HENNING ROWLAND J. KOPF BY ROGER MARSH ATTORNEY United States PatentEXPLOSIVELY A'CTUATED FASTENER DRIVING TOOL WITH SAFETY AND CARTRIDGEEX- TRACTOR MEANS Robert W. Henning and Rowland J. Kopf, Rocky River,and Roger Marsh, Hudson, Ohio, assignors, by mesne assignments, to OlinMathieson Chemical Corporation, a corporation of Virginia Y Filed Aug.z2, 195s, ser. No. 529,s42

a6 claims. (C1. 1-106) This invention relates to a tool for drivingfasteners and more specifically to an explosively-powered fastenerdriving tool.

lIn prior tools of this type it has generally been necessary to at leastpartially disassemble the tool to extract the expended cartridge and toreload the tool. yIn the past this has been accomplished in some mannersuch as removing the barrel from the tool or providing a hinged breechblock which may be swung clear of the barrel breech usually bydisconnecting the handle including the firing mechanism and breech blockfrom the barrel and barrel housing and swinging the members out of theway so that a stud and cartridge may be inserted into the breech end ofthe bore. In many tools the cartridge is inserted into a plug which isyreceived in the `breech of the barrel bore Whereuponit is necessary toremove the plug and extract the expended cartridge manice from these hotgases is objectionable in that the shielding makes the tool more bulkyand harder to handle.

An additional problem is that of the weight of the tool itself, sincemany of the -above mentioned problems could be quite simply solved butfor the resultant weight, and of course, cost of the tool. Furthermore,reduc#` tions in weight usually lead to a sacrifice of durability andstrength.

-lt is therefore an object of this invention to provide a tool in whichthe expended cartridge may be removed and a new cartridge and studloadedinto the breech of the barrel of the tool and be ready foruseWithout disassembling or loosening any portion of the tool.

A further object of this invention is to provide an extractorwhich ispositive in operation, rugged and substantially fool-proof.

ually. The addition of an extractor or extractor-ejector i to a tool mayeliminate the removable cartridge plug but lbecause of the higher gaspressure generated in a tool 'over the pressures in firearms, difficultymay be experienced in withdrawing the expended cartridge from thechamber in the barrel bore with an extractor built into the tool becauseof the forces required to overcome the tendency of the cartridge to jamthe chamber. The power to operate the extractor is usually supplied by aspring which may conveniently surround the barrel of the tool and thisis generally satisfactory. However, when the spring is exposed there isa tendency for it to collect foreign matter, such as dirt between thecoils thereby preventing the barrel from properly seating against the,breech block. .The higher operating pressures in a tool may also tendto cause the breech portion of the barrel to separate from the breechblock resulting in a protecti-ve shield which is usually providedsurrounding the ,muzzle of the barrel being forced away from the worksurface so that the shield is at least partially `ineffective. Suchseparation may also cause the cartridge case to rupture or jam in thechamber.

In normal operation the muzzle of the barrel is pressed against the worksurface at the time that the fastener is fired from the tool into thework surface. Thus the propellant gas violently impinges the worksurface and has a detrimental effect in scorching or otherwise marringthe Work surface itself and with certain materials, such as concrete,these gases may tend to blast away a portion of the surface. Toalleviate this condition pro- 'pellant gas venting ports may be providednear the muzzle of the barrel so that rather than the full volume andforce of the hot gas escaping through the muzzle of the bore asubstantial portion of the gas is'dissipated Another object of thisinvention is to provide a tool in which the barrel is locked against thebreech block during the initial expansion of the propellant Igas andwhich will be released automatically and immediately upon the stud beingprojected from the barrel.

Another object of this invention is to provide a breec locking mechanismwhich is automatic, simple in operation, rugged in construction andfool-proof.

Another object of this invention is to reduce the muzzle blast from thebarrel of the tool.

Another object of this invention is to dissipate the hot high velocitypropellant gases into a closed chamber.

Another object of this invention is to provide a propellant Vgasreceiving chamber which conforms to and harmonizes with the outsideconfiguration of the tool in such a manner that it will not interferewith or complicate the operation or handling of the tool.

Still another object of this invention is to reduce the weight of thetool by fabricating certain components from relatively light material insuch a way that the strength and durability of the tool is notmaterially affected while maintaining a satisfactory balance or feel ofthe tool as a whole.

Other objects and advantages will become apparent from the followingdescription and accompanying drawings in which:

Figure 1 is a parti-al sectional view of an embodiment of the inventionshowing the right side of a tool in the inoperative positon wth thebarrel fully extended from the housing and receiver;

Figure 2 is an enlarged view showing the breech portion of the barreland the extractor assembly of Figure l with the housing and receiverpartially broken away;

Figure 3 is a sectional view relating to other figures of the drawing,such as a fragment of Figure 4, showing an additional embodiment of abarrel return assembly;

Figure 4 is a partial sectional view of the left side of the tool ofFigure l but showing the tool in the operative. or ready-to-iireposition;

,Figure 5 is a left side view of the barrel shown in Figure 4 butremoved from the tool; v

Figures 6, 7 and 8 are sectional views taken on the lines VI--VL Vil-VII and VIII-VIII, respectively, in

vFigure 4;

.line 10-10 in Figure 9;

Figure l1 is a sectional view similar to Figure 10, but

illustrating thexbarrel Vtelescoped further inward in the tool housingand just before being fully seated in the operative or ready-to-fireposition;

Figure 12 is a sectional view similar to Figure l0, but illustrating thebarrel in the vready-to-lire position before' detonation of thecartridge;

Figure 13 is a sectional view similar to Figure l0, but illustrating thebarrel moved outwardly in the tool housingfrom the position illustratedin Figure l2, and with the extractorV withdrawing the cartridge from thebarrel chamber;

Figure 14 is a sectional view taken on the line 14--14 in Figure 12;

Figure 15 is a sectional view taken on the line 15-15 in Figure 12; and

Figure 16 is a side view partly in' cross-section showing still anotherembodiment of the tool positioned in operative abutment in theready-to-iire position.

The foregoing objects and advantages are accomplished in the followingnovel manner. The tool includes an outer aluminum housingv having -apistol-type hand grip and trigger guard and a hollow substantiallycylindrical extension which is provided' with a hand grip portion to aidin holding the tool. A hollow substantially cylindrical steel barrelreceiving member is inserted into and closely engages the bore of thealuminum housing extension. Integrally formed on the forward end of thebarrel receiver is a safety shield which surrounds the barrel muzzle andcooperates with the work surface in providing a closed chamber about themuzzle when the tool is in the ready-to-re position. The barrel isslidably received in the receiver. The barrel, receiver and housing areheld together by a set screw passing through aligned bores in thehousing and receiver with the inner end of the set screw received in avlongitudinal groove in the barrel to x the housing and receiver relativeto each other while permittingV sliding movement of the barrel in thereceiver. Gas escape ports pass through the barrel from the muzzle endof the bore to a gas expansion chamber formed by a portion of the wallof the bore of the receiver and a cutout portion in the barrel when thetool is in the operative or ready-to-iire position. The breech end ofthe barrel is fitted with a gas locking device to aid in maintaining thebarrel in the fully retracted position when the cartridge is fired. Thegas locking device includes an aperture extending from the barrel boreat a point immediately ahead-of the inner end of the cartridge to theouter surface of the barrel. This aperture has an enlarged portionextending inwardly from the outer wall of the barrel to receive a gaslocking plug. Upon tiring of the cartridge, the gas enters the apertureand forces the plug outwardly against the receiver thereby locking thebarrel in its fully telescoped position until the stud has passed thegas expansion ports and been discharged from the muzzle of the barrel.

`After firing the tool it is removed from contact with the Work surfaceat which time either a spring pressed plunger, a spring concentric withthe barrel and seated between the muzzle end 'of the barrel and thefront of the receiver, or a handle attached to the barrel, or anycombination thereof may be utilized in driving the barrel forwardly andoutwardly with respect to the housing and receiver from the operative orready-to-re position to the inoperative position. In one embodiment, asthe barrel moves outwardly from the housing the set screw which passesthrough apertures in the housing and receiver and has its forward endreceived in the slot in the barrel engages an extractor actuating ring,forcing the ring rearwardly to engage a pair of lugs extending laterallyfrom an extractor. The extractor is received Within and cooperates withthe breech portion of the barrel in-` forming a chamber to receive thecartridge. This form of extractor is preferred in tools using rim firedcartridges. Alternatively, if the tool is' designed for center firecartridgesan extractor mounted on the receiver and having a'hook portionengaged over the rimof the cartridge to prevent movement of thecartridge as the barrel returns to the inoperative position, may beutilized.

The cartridge firing means may be of any suitable type preferably suchas that disclosed in copending U.S. application Serial No. 334,817,`tiled February 3, 1953, now Patent Number 2,849,715 granted September2, 1958'. All movingparts including the firing mechanism are mounted onthe receiver, the trigger merely extending through a slot in thehousing. An additional feature of the tool resides in the provision of acutout portion through the housing' and receiver to permit a cartridgeandv stud to be inserted into the breech end of the barrel bore when thetool is in the inoperative or safe position.

The invention will be better understood from the following detaildescription:

The tool housing 1 has a longitudinal bore 2, a pistoltype hand grip 3for holding the tool ,trigger guard 4 and a cutout portion 5 tofacilitate insertion of a stud 6 and cartridge 7 into the tool. The studis shown as being attached to the cartridge, but a separate cartridgeand stud is equally applicable for use in the tool, depending on theindividual requirements of the job at hand. 'It is customary to'providea gas check of some sort, such as a polyethylene wad in the cartridge ora sabot on the stud to create a greater driving force against the stud.Propellent gas pressure ranges upward from 60,- 000 p.s.i. for a 38caliber tool to 90,000 p.s.i. for a 22 caliber tool. The rear end of thehousing is provided with a bore 8 having a reduced inner portion and theforward end of the housing is provided with a smooth bore`9 transverseto and intersecting. the longitudinal bore of the housing for purposesto be described hereafter. To reduce the weight of the housing it ispreferably fabricated from aluminum or other light material such asmagnesium. A steel or iron barrel receiver 10 is received within andsnugly engages the longitudinal bore 2 of the housing 1. A tool barrel11 is telescopically received in a longitudinal bore 12 in the barrelreceiver 10. The housing 1, receiver 10 and barrel 11 are held togetheras a unit by a set screw 13 passing through the transverse bore 9 in theforward end of the housing 1 and threadably received in an aligned bore14 in the receiver. 'I'he set screw has an inner end portion 15 which isreceived in a' -groove 16 in the upper portion of the tool barrel 11.This groove extends to the rear face of the breech of the barrel. Thehousing 1 and barrel receiver 10 are thereby fixed relative to eachother and the barrel is free to slide longitudinally with respect to thebarrel receiver. The receiver is provided with a cutout portion 17similar to and coinciding with the cutout portions in the housing 1, Thehousing is preferably provided with ridges 13 to aid in holding thetool.

The muzzle end 19 of the barrel is of a substantially smaller diameterthan the body of the barrel. In one embodiment of the invention shown inFigures 1, 4 and 5 a cylindrical cap 20 is fitted over the muzzle end ofthe barrel and is attached thereto by a crimped portion 21 engaging aperipheral groove 22 in the reduced portion 19 of the barrel muzzle. Thecap has a bore 23 aligned with and slightly larger than the barrel bore24 and protects the muzzle end of the barrel as the tool is pressedagainst a work surface.

In one embodiment of the invention shown in Figures 2 and 4, the breechend of the barrel bore 24 has a partially cutout portion 25 whichreceives an extractor 26. The breech end of the barrel bore and theextractor cooperate to provide a chamber for receiving the stud drivingcartridge 7. The extractor 26 has a groove 27 extending from a pointrearwardly from the end of the extractor nearest the muzzle of thebarrel or in other words from the front portion of the extractor andthrough therear face of the extractor. The breech end of the barrel isprovided with a threaded aperture which receives a set screw-,28,thenose of the set screw projecting into the groove 27 in the extractorto slidably retain the extractor in the barrel. A pair of lugs 29 extendtransversely from the rear-end of the extractor and are of slightly lesswidth than the diameter of the body of the barrel. These lugs arereceived in grooves 30 in the breech of the barrel. When the extractoris fully received in the barrel the rear faces of the barrel andextractor are flush with each other. The rear or breech end of thebarrel is cylindrical and of less diameter than the body of the barreland receives an extractor ring 31 which is freely movable, or in effectfloats, on the reduced portion of the barrel breech, as shown in Figuresl and 2. When the barrel assumes its outwardly fully inoperative safeposition, the ring 31 is moved rearwardly by the set screw 13 andengages the extractor lugs 29 forcing the extractor rearwardly therebywithdrawing the expended cartridge 7 from the chamber.

The extractor ring 31 has an internal diameter just slightly larger thanthe reduced diameter breech portion of the barrel and the inner surfaceof the ring may be slightly rounded so that the ring may assume theposition shown in Figure 2, but not to the extent that it will becomedisplaced from its seat on the barrel. The outside diameter of the ringis less than that of the barrel and the outside surface may also berounded. The set screw 28 prevents the extractor 26 from being removedfrom its seat in the barrel when in the position shown in Figure 1 or 2and this set screw also helps to maintain the extractor lugs 29 inproper alignment with the grooves in the breech of the barrel when thelugs have been moved rearwardly out of engagement with the grooves.Alternately, the lugs 29 and grooves 30 may be of sufficient depth sothat they will "not become disengaged from each other when the extractoris in its rearmost position. Grooves and lugs of this latter design havean additional advantage in that greater tolerances are permissiblebetween the ring 31 and the cylindrical reduced portion of the barrelbreech while still preventing removal of the ring during operation ofthe tool. The set screw 13 maintains the barrel 11 in proper alignmentwith the receiver and housing 1 through contact with the walls of thegroove 16 which extend through the reduced diameter breech portion ofthe barrel. The above referred to extractor is intended for use inconjunction with tools designed for rim re cartridges. When the tool isdesigned for use with center re cartridges another extractor to bedescribed hereafter is preferred.

Referring to Figures 4 and 8, one side of the barrel 11 is provided witha cutout portion 32 which cooperates with the receiver bore 12 to form aclosed chamber 33 when the barrel is in its fully retracted ready-to-reposition. Ports 34 are provided between the barrel bore 24 adjacent themuzzle and the cut out 32 so that the propellant gas which drives thestud forward through the bore of the barrel will be partially dissipatedthrough a plurality of these ports into the chamber 33 thereby greatlyreducing the muzzle blast from the tool. As will be noted from Figures 5and 8, ports 34 have a small opening into the barrel bore 24 to offer aminimum of disruption in the smooth bore and to maintain as muchstrength as possible; and a conical opening 34a enlarging outwardlytoward the barrel cutout 32, to offer a minimum resistance to the tlowof the propellant gas and at the same time to aid in dispersing the gasso that it impinges the receiver bore 12 over a wider area. Dischargingthe propellant gas into a chamber rather than through unprotected portsand into the open air has an additional advantage in that the chamberprotects the operator and nearby persons and material from possibleburns by exposure to the hot high velocity gas.

Immediately upon tiring the tool there is a tendency for the barrel tomoveforwardly away from the breech block 35a. This is caused by thereaction of the propellant gases tending to drive the stud forwardly andthe cartridge case 7 rearwardly. To alleviate this tendency a gaslocking device 35, shown in Figures 4, 7 and 16, is provided. This lockcomprises a lateral bore 36 through the barrel just ahead of the mouthof the cartridge 7. The outer portion of the bore is of greater diameterthan the portion opening into the barrel bore. Received in the outerportion of the bore is a gas locking plug 37 of polyethylene or othersuitable material such as leather. This plug conforms to theconfiguration of the enlarged portion of the bore, which is cylindricalalthough other configurations may be adopted. The inner portion of theplug is provided with a cupped portion 38 here shown as a substantiallyconical cavity. The function of the cup 38 is to permit the gas toexpand the top or inner portion of the plug into tight gas sealingcontact with the bore'. The smaller and larger portions of the bore arejoined by a conically shaped shoulder to permit more rapid and evendispersal of the gas to the cupped portion 38 of the plug 37.

Upon firing the tool the propellant gas immediately enters the bore 36and engages the cup portion 38 of the plug 37 forcing the plug outwardlyinto tight frictional engagement with the bore 12 of the receiver. Aspreviously mentioned the cupped portion 38 of the plug 37 permits thepropellant gas to expand this portion of the plug into tight gas sealingengagement with the walls o f the enlarged portion 36a of the bore 36.As the stud 6, driven by the propellant gas passes the ports 34 leadingto the gas expansion chamber 33 and leaves the muzzle of the tool thepressure on the gas locking plug 37 is dissipated and the plug isreleased from its tight frictional engagement with the receiver bore 12.

After the stud 6 has been driven into the work surface W the tool isremoved from its operative position with the barrel muzzle cap 20 andshield 39, on the muzzle end of receiver 10 engaging the work surfacewhereupon, in one embodiment of the invention shown in Figures 1 and 4,a spring pressed plunger 40 drives the barrel forwardly. A spring 41 isof sucient strength so that as the tool is suddenly removed from thework surface the force of the spring will be suicient to drive theextractor ring 31 into engagement with the set screw 13, extracting theexpended cartridge 7 from the breech of the barrel. The spring pressedplunger 40 is received in a bore 42 in the receiver and has a head 43eccentric to the longitudinal axis of the plunger. The spring 41 isreceived between head 43 and a disk 44. An adjusting screw 45 passesthrough the bore 8 in the housing 1 and is threadably received in athreaded bore 46 in a plug 47 in the rear of bore 42 in the receiver 10.The plug 47 may be secured in the receiver 10 in any convenient manner,such as by the threaded connection shown. By adjusting the screw 45inwardly or outwardly the pressure of the spring 41 may be adjusted sothat the plunger will drive the barrel forward with the proper force.

The barrel may be provided with a handle 47a extending transverselythrough the cut out portions 5 and 17 in the housing 1 `and receiver 10to permit the barrel 11 to be forced forward manually, to eject thecartridge 7, either independently of or in conjunction with the springpressed plunger 4G. Notches such as 47h may be provided in the housingand the barrel receiver 10 to permit full travel of the barrel 11between the inoperative position shown in Figure l and the ready-to-reposition shown in Figure 4.

Figure 3 shows another embodiment of a barrel return mechanism which maybe used either in conjunction with the spring pressed plunger returnmechanism described above, or independently of the plunger. In thisembodiment a compression spring 48 is received on the front end of thebarrel 11. One end of the spring engages a seat 49 provided in theforward portion of the barrel receiver 10 and the other end of thespring engages an outwardly extending flange 50 on the muzzle end ofthebarrel.

As shown in the drawing (Fig. 3) the flange 50 is formed integrally witha fitting 51 or is formed integrally with the cap 20 (Fig. 4) either ofwhich is secured on the muzzle end of the barrel as by the threadedconnection shown. In Figure 4, after modification according to Figure 3,receiver 10 may be longer and the front end of the bore of the receiver10 is enlarged adjacent the shield 39 to provide seat 49 and to formwith the front end of the barrel 11 an annular place to hold spring 48adjacent a suitable muzzle fitting such as 20, or 51 (Fig. 3). Theremaining structure of this embodiment may be the same as any of theembodiments previously described. This embodiment of the barrel returnmechanism provides for assured biased return of the barrel to its fullyextended inoperative position and thereafter maintains theI barrel inthis position. By providing the tool with both the spring pressedplunger assembly 40, etc., and the spring 48 about the barrel, as shownin Figure 16, an additional advantage is obtained since the additionalforce of the combined springs act in conjunction with the center firecartridge extractor, to be described hereinafter, to remove the expendedcartridge from the chamber, while additional force on the part of theoperator to properly seat the muzzle of the tool against the worksurface is required only during the very last portion of barrel travel.

In Figure 16, the tool is shown thrust forwardly with its muzzle cap 120and the periphery of the skirt of its shield 139 abutted against worksurface W. In this position the tool is in ready-to-lre. The toolincludes a barrel 111 having a bore 124 in alignment with the bore 123of cap 120. The latter forms one abutment for the cornpression spring148 the other end of which seats in spring seat 149 provided in theforward portion of the modied barrel receiver 110 so that the spring maybe received on the front end of barrel 111, similar to the manner spring48 is received on the tool of Figure 3. The tool housing 101 accordinglyis modified at its front end.

The barrel receiver 10 may be provided with any other desired type ofshield in place of shield 39 or, if so desired, the shield may beeliminated.

In assembling the tool the plunger 40, spring 41 and disk 44 areinserted into the bore 42 in the rear of the receiver 10 and secured inplace by plug 47. The firing mechanism is assembled in the receiver.-The extractor ring 31 is positioned on the reduced diameter breechportion of the barrel 11 and the extractor 26 is then inserted into itsseat 25 in the barrel. Set screw 28 is then screwed into the threadedaperture in the breech portion of the barrel to retain the extractor inits seat. The extractor lugs 29 prevent the ring 31 from being removedfrom the barrel. The locking plug 37 is inserted into the aperture 36and the barrel is then inserted into the receiver bore 12, care beingtaken not to damage the gas locking plug 37. The receiver 10 is theninserted into the housing bore 2. Aperture 9 in the housing 1 is alignedwith threaded aperture 14 in the receiver, set screw 13 is insertedthrough bore 9 and threaded into bore 14 until the nose port-ion 15 ofthe set screw is received in the slot 16 of the barrel to a sufficientextent that the nose portion 15 will contact the walls of the groove 16adjacent the reduced breech portion of the barrel when the barrel isfully extended in the inoperative position. Adjusting screw 45 is thenscrewed through the threaded bore 46 in plug 47 to engage disk 44 andcompress spring 41. The trigger is inserted through aligned slots in thehousing and receiver and a pivot pin is passed through a hole 4a in thehousing and seated in the receiver and trigger pivot hole to secure thetrigger in place.

In the embodiments utilizing the barrel return assembly shown in Figure3 the tool is assembled lin the manner previously described, noting thatthe spring plunger assembly may or may not be utilized. Following the-above describedY assembly procedure spring 48 is slipped over thebarrel 11 and fitting 51 is secured to the muzzle of the barrel.

In the embodiment of the tool using center fire cartridges the extractormechanism shown in Figures 9 through 14 may be utilized. Figure 9 showsthe barrel 11, with a cartridge 59 in the chamber, midway of its path oftravel rearwardly in the receiver and housing'preparatory to ring thecartridge. As best shown in Figures 10-12 in this embodiment theextractor 60` is retained in a slot 61 `in the receiver 10 by a splitspring ring 62 which is received in a circumferential groove 63 in thereceiver 10. The slot 61 is just wide enough to receive the flatextractor 60 so that there is no appreciable up and down play betweenthe extractor and the slot. The extractor may move forwardly andrearwardly, being shown in its rearmost position in Figures 1l and 12`and its forwardmost position in Figure 13. By comparing Figures 11 and12 it will be seen that the extractor 60 may also move inwardly andoutwardly with a pivotal movement in the slot 61. In Figure 11 thebarrel 11 is shown just before seating against the breech 4block 35a.The rim on the cartridge has engaged a cam surface y64 on the extractor60 pushing the extractor to its rearmost position as shown and alsoforcing the extractor outwardly against the resistance of the splitspring ring 62. In Figure 12 the tool is in `its ready-to-re positionwith an extractor hook portion 65 engaging the forward edge of thecartridge rirn. In this position the engagement between the taperedouter surface 66 of the extractor and the split spring ring 62 tends toprevent the extractor from moving forwardly. It will be noted that thebarrel 11 has a cutout portion 67 to receive the extractor hook portion65 and that the receiver has a lug 63 on its inner wall 12. `Figure 13shows the tool after tiring with the barrel 11 started toward theinoperative position. The extractor hook 65 is in engagement with therim of the cartridge 59 and the cartridge is shown partially extractedfrom the barrel chamber. In this position a shoulder 69 on the extractoris in engagement with the lug 68 on the inner surface 12 of thereceiver. The lug 68 may be formed integrally with the receiver 1) or itmay be riveted, welded or secured to the receiver in any appropriatemanner. It should also be noted that in this embodiment a recess 7@ forthe cartridge rim Iis provided in the breech block portion of thereceiver 19, however, the recess could equally well be formed in thebarrel or omitted entirely.

In assembling a tool having this type of extractor it is merelynecessary to properly place the extractor 60 in the slot 61 and insertthe split spring ring `62 in the slot 63 before inserting the receiverinto the housing bore 2.

As was mentioned earlier in the description, the tool housing 1 ispreferably fabricated from aluminum or some other light metal such asmagnesium in order to reduce the total weight of the tool. It should benoted that the entire rear portion of the tool including the pistol gripand trigger guard is aluminum and is rigidly secured to the tool by thelongitudinal extension forming the bore 2 which receives the receiver1t) and that the aluminum housing 1 has no moving contact relative tothe remainder of the tool to cause wear and premature replacement.

In operation cartridge 7 or 59 and stud 6 are inserted into the breechof the barrel bore 24 through the loading cutouts 5 and 17 in thehousing 1 and receiver 1?, respectively. The barrel muzzle cap 2% or 51is pressed against the work surface into which the stud is to be drivenuntil the breench of the barrel seats against the breech block 35a ofthe receiver bore and the front of the shield 39 is adjacent the worksurface W. The trigger is then depressed ring the cartridge. Immediatelyafter the cartridge 7 has been fired starting the stud 6 through thebore of the tool, the propellant gas pressure enters the aperture 36causing the gas locking plug 37 to frictionally engage the receiver bore12 locking the barrel in place. As the stud passes the gas relief ports34 the propellant 4gas expands into the gas expansion chamber 33relieving the pressure on the plug 37 and permits the plug to releaseits hold on the receiver. After the stud has been driven into the worksurface and as the tool is removed from the work surface, the barrelwill be forced forward by the spring pressed plunger 40, manually byhandle 47a, and/or the spring 4S so that in the embodiment employing rimred cartridges the extractor ring 31 engages the set screw 13 and isforced rearwardly against the extractor lugs 29 driving the extractor 26rearwardly and partially out of the barrel. As may be seen in thedrawing, the extractor has a shoulder which engages the iiange on thecartridge so that the cartridge is drawn out of the barrel bore and maybe removed to permit the insertion of another stud and cartridge.

It is to be understood that although the foregoing description of thisinvention specilies certain metals such as. steel for the barrel andbarrel receiver member and related moving parts and aluminum ormagnesium or other relatively light metal for the housing member as wellas polyethylene or leather which should preferably be lubricated in somemanner such as by being saturated by oil, this application is not to beso limited since many other materials known in the arts may besubstituted for these materials. However, the housing member ispreferably of substantially lighter material than the remainder of thetool. It is also to be understood that although the invention isdescribed with particular reference to an explosively powered fastenerdriving tool, many features of the invention may be utilized in otherfields such as in perforating, riveting or impact deforming or workingof metals and many other environments wherein it is necessary to drive amember with high velocity and/ or force. Furthermore, in the firearm andrelated fields certain features such as the extractors, gas lockingdevice, the barrel return mechanisms and the light weight housing mayhave additional utility. Additionally it should be noted that althoughthe tool is described with particular reference to the utilization of anexplosive power charge contained in a cartridge, certain aspects of thetool are equally applicable to tools powered by compressed air or otherfluids and to tools wherein the power is provided by a spring or othersimilar mechanical means. Although many specific embodiments and detailsare set forth in the foregoing, it will be understood that variouschanges may be made without departing from the spirit and scope of thisinvention and that this invention is therefore not to be limited to suchembodiments and details except as set forth in the appendent claims.

We claim: 1. In a tool of the class described, the combination of abodyportion telescopically receiving a tool barrel hav- 'fastener may bedischarged, blast shield means adapted to extend laterally around saidmuzzle end means to 4reduce the force of said propellant fluid at themuzzle end of said barrel as said fastener is driven through saidbarrel` bore, said force reducing means comprising a plu- `rality ofpassageways at the muzzle end of said bore between the interior of saidbarrel bore and the outer snrface of said barrel and opening into alongitudinal groove opposite said heavy wall, said passageways and saidgroove forming a closed chamber being of suliicient size "tosubstantially reduce the muzzle blast of the propellant uid when saidbarrel and body portions are telescoped sutiiciently until said portionsurrounds the grooved part of the barrel, said chambercomprising both asingle cutout portion of the outer surface of the barrel intermediatethe ends of said barrel and said passageways expanding outwardly towardsaid cut-out portion.

, 2. In a fastener .driving tool of the class described, the.combination of a tool barrel slidably received ina toolV body portionfor sliding movement from an inoperative to a ready to fire position,and pressure sensitive means responsive to ring to lock said barrel inits ready-to-iire position during the time of tiring said tool, saidlocking means comprising a member mounted in said barrel for movementinto engagement with said body portion.

3. In a tool of the class described, a tool body slidably receiving atool barrel having a bore into which a propellant uid may be discharged,means to lock said barrel relative to said body portion, said meanscomprising a passageway between the barrel bore and the outer surface ofsaid barrel and means in said passageway to Vtightly engage an adjacentsurface on said tool body when said iuid is discharged into said barrelbore.

4. In the tool of claim 3, said means received in said passagewaycomprising a plug slidably received in said passageway and having meansproviding a iiuid tight seal with said passageway so that the fluiddischarged into the barrel bore will force said plug outwardly and intoengagement with said tool body.

5. In a tool of the class described, a barrel portion having a chamberfor receiving a propellent gas generating cartridge and an extractormechanism for removing said cartridge from said chamber, said extractormechanism comprising an extractor element telescopically received insaid barrel portion, an internal surface of said extractor elementproviding a longitudinal segmental portion of said chamber wall,abutment means on said extractor element projecting laterally outwardlywith respect to the chamber axis, means slidably mounted on said barrelportion to engage said laterally extending abutment means on saidextractor element to move said extractor element axially outwardly fromsaid barrel portion thereby sliding said cartridge from said chamber,and means carried by said barrel portion for abutment with said elementat the extremity of its outward extractive movement to prevent removalof said extractor element from said barrel portion,

6. In a tool of the class described, the combination of means forholding said tool operatively positioned in the hands of an operator,said means consisting of a housing, said housing being open at one end,a barrel receiving member and a barrel both coaxially receivable in saidhousing and in said member respectively, said ihousing at leastpartially surrounding, and closely engaging in fixed relationship tosaid barrel receiving member, said barrel receiving member having alongitudinal bore open at one end telescopically receiving said barrelmovable therein with frictional retention, said barrel having a bore forreceiving a projectile fastener to be propelled through said barrelbore, positioning means tending to maintain said barrel positionedtelescopically outwardly with respect to said receiving member, iiuidforce generating cartridge initiating means in said member adjacent thebreech end of said barrel to project said fastener through said barrelbore when said barrel is fully received within said receiving memberbore, muzzle blast reducing means in said barrel and member to reducethe force of the fluid at the muzzle of said barrel bore, locking meansto lix said barrel in its fully received position in said receivingmember bore when said barrel is in its fully received positionimmediately upon introduction of said propellent force into said barrelbore and lateral port means in said housing and member to permitinsertion of a projectile into said barrel bore and loading andextraction of said cartridge.

7. In the tool of claim 6 said means for holding said tool in itsoperative position comprising a pistol-type grip at an extremity of saidhousing and a tube at the opposite extremity of said housing.

8. The tool of claim 7 wherein said housing is fabricated of a materialof substantially less density than that of said receiving member andbarrel.

9. The tool of claim 6 wherein said barrel receiving member issubstantially closed at one end and is provided with means to shield theoperator from richocheting fasteners and expended propellant fluid, saidshielding means extending laterally with respect to the longitudinalaxis of said receiving member bore and from the open end of said4receiving member bore.

10. The tool of claim 6 wherein said positioning means comprises acompression spring telescopically received on said barrel and having oneend engaging said receiving member and the other end engaging anabutment on the end of said barrel.

11. The tool of claim 6 wherein said muzzle blast reducing meanscomprises a passageway from the bore of said barrel to the outer surfaceof said barrel, said passageway opening into a closed chamber.

l2. The tool of claim 6 wherein said locking means comprises apassageway between the bore of said barrel and the surface of saidbarrel adjacent the surface of said bore of said receiving member, and aplunger telescopically received in said passageway to tightly engagesaid receiving member bore when said propellant fluid is introduced intosaid barrel bore.

13. The tool of claim 6 wherein said port means comprises alignedopenings cut out of said housing and said barrel receiving member.

14. In a tool having a barrel through which a fastener is driven by theforce of an explosive cartridge, a housing providing means for holdingsaid tool operatively positioned in the hands of an operator, saidhousing having a bore coaxially surrounding and closely engaging in xedrelationship a barrel receiving member carrying cartridge initiatingmeans, said barrel receiving member having a longitudinal boretelescopically receiving a barrel, positioning means for maintainingsaid barrel telescopically outwardly in said barrel receiving bore andinto an inoperative position with respect to said initiating means ofthe receiving member, means providing a closed chamber when said tool isin the operative position with the barrel fully received in said barrelreceiving member bore, and `a passageway through the barrel wallconnecting the barrel bore and said closed chamber, said chambercomprising a portion of the outer surface of said barrel and theadjacent surface of said receiving member bore spaced from said barrelsurface, aligned cutout portions in the walls surrounding the bores ofsaid housing and receiving members, said portions forming an openingthrough which said fastener and said cartridge may be inserted into thebore of said barrel when said barrel is in the inoperative position,means to tix said housing and receiving member relative to each other,said fixing means having a portion extending into said barrel to preventrotation of said barrel in said barrel receiving member bore and saidextending portion abutting with shoulder means on said barrel forpreventing removal Of said barrel from said barrel receiving memberbore, the last said means comprising a pin extending through saidhousing and receiving member and projecting into a longitudinal groovein said barrel.

15. In a tool of the class described, a tool barrel telescopicallyreceived within a barrel receiving member, said barrel receiving memberhaving a longitudinally extending side port and being received within abore in a housing member also having a longitudinally extended side portalignable with said rst side port, said barrel having a recess on oneside of its exterior in communicating relationship with its bore, meansto x said barrel receiving member and said housing relative to eachother with said ports in alignment and to prevent rotation in andremoval of said barrel from said barrel receiving member whilepermitting movement of said barrel from a retracted port closingposition to an extended port opening position, said means comprising apin passing through said housing and said barrel receiving member havingan end received in a groove in said barrel separate from said barrelrecess.

16. In the tool of the class described, a tool barrel having `alongitudinal fastener projecting bore and a barrel sleeve membertelescopically receiving said barrel with limited relative telescopingmovement between said barrel and member, an intermediate portion of theouter surface of said barrel having a groove on substantially all of oneside of its circumference, said groove being completely enclosable bysaid member to form an otherwise closed expansion chamber for residualgas, said barrel having a plurality of exhaust passageways adjacent themuzzle end extending between said bore and groove, said passagewaysexpanding outwardly from said bore to said groove.

17. In a tool of the class described, a laterally ported housing havinga bore open in one end, a laterally ported barrel receiver in said boreand having a tubular portion open at one end, a barrel telescopicallyreceived in the bore of said tubular portion, and means to operativelysecure together said housing, receiver and barrel, and maintain saidports in alignment, said means comprising a pin passing through saidhousing and receiver, and projecting into said barrel, said housingbeing of a substantially less dense material than said receiver andbarrel.

18. In a tool of the class described, a housing having a bore openforwardly at one end, closed at the opposite end, and ported adjacentsaid forward end in one lateral direction, a barrel receiver mounted insaid bore and having a tubular portion with a bore open at one end andclosed at the opposite end, opposite which end said portion is alsolaterally ported in said direction, a barrel having lateral passagewaysadjacent the muzzle on a side disposable in a direction substantiallyopposite said ports and received in said tubular portion bore fortelescoping movement between a telescoped position and an extendedposition, an exhaust chamber between said barrel and tubular portion onsaid opposite side adapted for communication with said passageways,means to operatively secure together said housing, receiver, and barrel,while permitting said movement, with said ports maintained aligned fortool loading and extraction in said direction in said extended positionand with said chamber and passageways maintained in communication onsaid opposite side in said telescoped position, said laterally portedends of said housing and receiver forming a breech structure adapted toopening in said direction, a pistol type hand grip projecting laterallyfrom said closed end in a direction substantially transverse of saidother directions.

19. In a tool of the class described, a housing having a bore open atone end, a barrel receiver in said housing bore, said housing andreceiver being laterally ported on the same side for loading andextraction, said barrel receiver having a tubular portion open at oneend, a barrel telescopically received in the tubular portionof saidbarrel receiver, said barrel having a slotgenerally parallel to thelongitudinal axis of said tubular portion, stop means positionedadjacent each of the longitudinally spaced ends of said slot, alignedapertures through the walls of said housing and said tubular portion anda pin received in said apertures and having one end received in saidslot in said barrel, whereby said housing and said barrel receiver arexed with respect to each other with said ports in alignment and thetelescopic travel of said barrel in said tubular portion is restrictedbetween said stop means by said pin.

20. In a tool of the class described, a housing having a bore open atone end, a barrel receiver in said bore and having a tubular portionopen at one end, a barrel telescopically received in the tubular portionof said barrel receiver, said barrel having a breech and muzzle and aslot extending from a breech end to a muzzle end and generally parallelto the longitudinal axis of said tubular portion, said slot extendingover the major portion of the length of said barrel, aligned aperturesthrough the walls of s'aid bore and said tubular portion 13 adjacent theopen ends thereof and a pin received in said apertures and having oneend received in said slot in said barrel, and means to prevent removalof said barrel from said tubular portion, said means comprising anabutment at the breech end of said slot.

21. In a tool of the class described, the combination of a body portiontelescopically receiving a tool barrel having a bore through which afastener is driven by the force of a propellant fluid introduced intosaid bore and having a ybarrel Wall heavy on at least one side relativeto said bore, said bore having a muzzle end from Which said fastener maybe discharged, blast shield means adapted to extend laterally aroundsaid muzzle end, means to reduce the force of said propellant fluid atthe muzzle end of said barrel as said fastener is driven through saidbarrel bore, said force reducing means comprising a plurality ofpassageways at the muzzle end of said bore between the interior of saidbarrel bore and the outer surface of said barrel and opening into alongitudinal groove opposite said heavy wall, said passageways and saidgroove forming a closed chamber being of sufficient size tosubstantially reduce the muzzle blast of the propellent uid when saidbarrel and said body portion are telescoped until said portion surroundsthe ,25

grooved part of the barrel.

22. In a tool of the class described, the combination of a body portiontelescopically receiving a tool barrel having a bore through which afastener is driven by' the force of a propellant Huid introduced intosaid bore, and having a barrel wall heavy on at least one side relativeto said bore, said bore having a muzzle end from which said fastener maybe discharged, blast shield means adapted to extend `laterally aroundsaid muzzle end, means to reduce the lforce of said propellent uid atthe muzzle end of said barrel as said fastener is driven through saidbarrel bore, said force reducing means cornprising a plurality ofpassageways at the muzzle end of said bore between the interior of saidbarrel bore and the outer surface of said barrel and opening into alongitudinal groove opposite said heavy wall, said passageways and saidgroove forming a closed chamber being of sufficient size tosubstantially reduce the muzzle blast of the propellent fluid when saidbarrel and body portion are telescoped until said portion surrounds thegrooved part of the barrel, said closed chamber being defined bysurfaces of said barrel disposed externally of the barrel bore and anopposite wall of the body portion surrounding said barrel.

23. In the tool of claim 22, the outer surface of said barrel whichdefines said closed chamber comprising a cut out portion extending over'a substantial circumferential part intermediate the full ends of thebarrel,` said passageways opening into said cut out portion.

24. In a fastener driving tool of the class described, the combinationcomprising a tool barrel having a bore adapted to receive a fastener anda force applying fluid for driving said fastener through said bore andhaving a muzzle adapted to be placed in abutment with a workpiecesurface, said barrel being telescopically received in a tool body forsliding movement of said body with respect to said tool barrel from aninoperative to an operative position, and means to lock said body in itsoperative position immediately upon discharge of said uid into saidbarrel bore.

2S. In a fastener driving tool of the class described, the combinationcomprising, a tool barrel having a bore adapted to receive a fastenerand a force lapplying fluid for driving said fastener through said boreand having a muzzle adapted to be placed in abutment with a workpiecesurface, said barrel being telescopically received in a tool body forsliding movement of said body with respect to said tool barrel from aninoperative to an operative position, means to release said fluid intosaid barrel bore when said body is in said operative position, and means'to lock said body in its operative position immediately upon release ofsaid lluid into said barrel bore.

26. In a tool of the class described, a combination of a tool bodyincluding means telescopically receiving a tool barrel, said barrelhaving a bore adapted to receive Va fastener to be driven therethroughby a fastener propelling force and having a muzzle adapted to be placedin abutment with a workpiece surface, said barrel and body beingslidable with respect to each other from an inoperative to an operativeposition, and means to lock said barrel and body in their operativeposition immediately upon introduction of said fastener propelling forceinto said barrel bore. 27. In a tool of the class described, a `barrelhaving a chamber for-receiving a fastener propelling cartridge, saidbarrel being slidably received within a barrel sleeve portion of saidtool, cartridge extractor means carried in captive relationship on saidbarrel adjacent said chamber comprising a sliding segment forming partof said chamber and having opposed lateral projections and a segmentactuating ring slidably mounted in captive relationship on said barrelfor abutment with said projections, and stop means on said barrel sleeveabuttable with said ring to retain said sleeve and barrel together andto extract said cartridge from said chamber when said sleeve is movedto' adjacent` the extremity of its withdrawal from said barrel. f

`2,8. Ina tool of the class described, a body member having an openfront end communicating with a bere telescopicallyreceiving a barrelhaving a muzzle at the front end'and a chamber at its breech forreceiving a cartridge shouldered at its base, said body member beingtelescopically movable from an extended inoperative position toatretracted position and having a pistol type hand grip extendinglaterally, said member also having a lateral port longitudinallyextending over a major part of the length of said body member andopening to one Side of said grip, extractor means telescopicallyreceived in said bore adjacent said chamber and movable into operativeengagement only with the shoulder of said cartridge for withdrawing saidcartridge from said chamber by engagement with said shoulder when saidbody member is moved from the operative to the inoperative position,said lateral port in saidbody member communicating with said bore backof said breech and means on said body and barrel disposed between saidbreech and open end engageable to .move-said'extractor means so as toWithdraw said cartridge from said chamber when said body is telescopedfrom its operativeposition at which said port is closed by saidlbarrel,vto adjacent its inoperative position with respectto'rsaid barrel atwhich position said port is fully opened. Y

l A29.' Inv a tool of the class described, a body having a socket havingone open end telescopically receiving a barrel, said barrel having abore for coaxially receiving a fastener to be propelled through saidbore by `a uid force introduced into said bore, positioning meansmounted between portions of said body and barrel tending to maintainsaid barrel inoperatively positioned telescopically outwardly withrespect to said socket, means mounted on said body to release saidfastener driving fluid force when said barrel is fully telescoped intosaid socket, means adjacent the barrel muzzle to reduce the force ofsaid fluid at the muzzle end of said barrel as said fastener is driventhrough said barrel bore, and locking means mounted on said barrel toact between said body and barrel to fix said barrel in its fullyreceived position in said socket immediately upon introduction of saidfluid force into said barrel bore.

30. In a tool of the class described, `a body member having alongitudinal bore open at one end and substantially closed at the otherend, said bore telescopically receiving a barrel having a bore throughwhich a projectile may be propelled by a propellant force released intosaid barrel bore, positioning means mounted on at least one of said bodymember and barrel for normally maintaining said barrel inoperativelypositioned telescopically outwardly with respect to the bore in saidbody member, means carried in said body member to release said force todrive said projectile through said barrel bore when said barrel isoperatively positioned fully received within the bore in said bodymember, means positioned adjacent the barrel muzzle to reduce theintensity of said propellant force at the muzzle end of said barrelbore, and locking means mounted to act between said body member andbarrel to ix said barrel in its fully received position in said barrelbore immediately upon introduction of said propellant force into saidbarrel bore.

31. In the tool of claim 30, the addition of means for holding said toolin its operative position, said means comprising a pistol type hand gripat an extremity of said body member, and a barrel receiving tube in theopposite extremity of said body member, saidl tube lining said bore insaid body member.

32. The tool of claim 31, wherein said body member comprises an outerhousing member including said means for holding said tool and saidbarrel receiving tube is received in the bore of said housing member,said housing being fabricated of a material of substantially lessldensity than that of said receiving tube and barrel.

33. The tool of claim 32 wherein said barrel receiving tube has an openend and wherein the open end of the receiving tube is provided withshielding means to protect the tool operator from debris mobilized bythe residue of the propellent force at the barrel muzzle, said shieldingmeans extending laterally with respect to the longitudinal axis of thetool.

34. The tool of claim 30 wherein said positioning means comprises acompression Spring telescopically received on said barrel and having oneend lxed with respect to said rst member and the other end xed withrespect to said barrel.

35. In a tool of the class described, a body member having alongitudinal bore open at one end and substantially closed at the otherend, said bore telescopically receiving a barre1 having a bore throughwhich a projectile may be propelled by a propellant force released intosaid barrel bore, said member having a longitudinally extending lateralport, positioning means mounted on at least one of said body and memberand barrel for normally maintaining said barrel inoperatively positionedtelescopically outwardly with respect to the bore in said body member,means carried in said body member to release said force to drive saidprojectile through said barrel bore when said barrel is operativelypositioned fully received within the bore in said body member, means forextracting a cartridge from the bore of said barrel into the bore ofsaid member adjacent said bore,

16 locking means mounted to act between said body member and barrel to xsaid barrel in its fully received position insaid barrel boreimmediately upon introduction of said propellant force into. said barrelbore, and a spring pressed plunger projecting through the substantiallyclosed end of the bore in said body member for engaging said barrel whensubstantially fully received in said bore, whereby said plunger furtherbiases said barrel so received outwardly with respect to said bore toinitially act against said locking means after said release andintroduction and at least initiate operation of said extraction means.

36. In a tool of the class described, a tool body having a socket openat one end and substantially closed at the other end, a tool barreltelescopically received in said socket and operatively positioned insaid socket when one end of said barrel is substantially in abutmentwith the substantially closed end of saidsocket, said body beingtelescopically movable on said barrel from an extended inoperativeposition to a fully telescoped position corresponding to said operativeposition, safety means tending to maintain `said barrel telescopedoutwardly with respect to the substantially closed end of said socket,said means comprising a spring pressed plunger of a length short of saidbody movement for engaging Said barrel only over that terminal part ofsaid movement when said barrel is in proximity with said substantiallyclosed end.

References Cited in the file of this patent UNITED STATES PATENTS Re.11,800 Wesson Jan. 9, 1900 1,317,419 Bergman Sept. 30, 1919 1,388,363Miller Aug. 23, 1921 2,008,362 Littlehale July 16, 1935 2,045,333 PipesJune 23, 1936 2,112,144 Coupland Mar. 22, 1938 2,457,354 Dial Dec. 28,1948 2,679,645 Erickson June 1, 1954 2,692,383 Catlin Oct. 26, 19542,702,902 Portouw Mar. 1, 1955 2,705,323 Bossong Apr. 5, 1955 2,719,300Walker Oct. 4, 1955 2,771,323 Skumawitz Nov. 20, 1956 2,773,259Broughton et al. Dec. 11, 1956 FOREIGN PATENTS 6,491 Great Britain of1914 506,769 Belgium Nov. 15, 1951 283,155 Switzerland Sept. 16, 19521,040,789 France May 27, 1953 1,073,899 France Mar. 24, 1954 1,083,665France June 30, 1954 1,083,993 France June 30, 1954 UNITED STATES PATENTOFFICE CERTIFICATION OF CORRECTION Patent No. 2x95?, 176 October 25,1960 Robert W. Henning et al.

It is hereby certified that error appears in the above numbered pat entrequiring correction and that the said Letters Patent should read ascorrected below.

Column IO, line 61 and 62, strike out "when said barrel is in its fullyreceived position" and insert the same after bore and before the commain line 60, same column.

Signed and sealed this 25th day of April 1961.

(SEAL) Attest:

ERNEST wr, SWTDER v DAVTD E. LADD Attesting Officer Commissioner ofPatents UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION PatentNo. 2,957,176 October 25, 1960 Robert W. Henning et .alla

It 'is hereby certified that error appears in the above numbered pat-fent requiring correction and that the said Letters Patent should read ascorrected below.

Column IO, line 61 and 62, strike out "when said barrel is in its fullyreceived position and insert the same after "bore" and before the commein line 60, same columno Signed and sealed this 25th day of April 1961.

(SEAL) Attest:

ERNEST W, SWIDER DAVID Le. LADD Attesting Officer Commissioner ofPatents

